Crystal, Long Lake concerns

February 23rd, 2012

By Gail Geraghty

Staff Writer

HARRISON — Both of Harrison’s lakes, Crystal Lake and Long Lake, are of high concern for water quality, and Island Pond rated in the moderate/high category in last year’s water quality testing done by Lakes Environmental Association, selectmen learned last week.

Of greatest concern is Crystal Lake, the LEA’s Colin Holme told the board.

“There’s been a long, slow decline in water clarity in Crystal Lake,” he said. “It’s on our watch list.” The high degree of concern category is reserved for lakes that routinely show signs of phosphorus recycling, where fishing is regularly impacted by oxygen depletion or have had algae blooms in the past.

Holme said Crystal Lake’s Secchi disk reading average was 5.8 meters, down from the long-term average of 6 meters. “Crystal Lake’s deep, well-oxygenated water column is good for the lake’s cold water fishery, however consistently declining water clarity readings are a major concern,” states the report, which is available online at LEA’s website, www.mainelakes.org

In Long Lake, “consistent and pronounced dissolved oxygen depletion in the deeper waters is negatively affecting the lake’s cold water fishery,” the report states. “During seasons with a late fall turnover, these low oxygen conditions are prolonged, making the problem even more severe.”

Island Pond rated moderate/high concern, with a Secchi disk reading of 5.3 meters, down from the long-term average of 6 meters, “because of low oxygen conditions and periodically elevated phosphorus levels in the bottom waters.”

Around half of the 37 lakes sampled overall by LEA in 2011 showed “worse than average” in both their clarity readings and their chlorophyll readings.

“Unfortunately, phosphorus levels were above average on over 70% of this area’s lakes, meaning that overall, more nutrients were coming into Lake Region waters than usual,” the report states. Factors that were likely responsible for these conditions were the wetter than normal summer and several intense storms, such as one at the end of July when nearly three inches of rain fell in a 24-hour period, and Hurricane Irene in August. Also, July was hot and was recorded as the warmest month ever at the Portland Jetport, the report states, and warm conditions are conducive to algae.

“Sadly, warmer and wetter conditions are what the best climate models are predicting for our region, so the negative trend this past summer could soon become the norm, unless different policies are adopted to reduce carbon emissions.”